Berkeley DB Reference Guide: System Installation Notes

File utility /etc/magic information

The file(1) utility is a UNIX utility that examines and
classifies files, based on information found in its database of file
types, the /etc/magic file. The following information may be added
to your system's /etc/magic file to enable file(1) to
correctly identify Berkeley DB database files.

The file(1) utility magic(5) information for the
standard System V UNIX implementation of the file(1) utility
is included for both big-endian (e.g.,
Sparc) and little-endian (e.g., x86)
architectures.

The file(1) utility magic(5) information
for Release 3.X of Ian Darwin's implementation of the file
utility (as distributed by FreeBSD and most Linux distributions)
is available from magic.txt. This
information is correct for both big-endian and little-endian
architectures.